1. Field of the Invention
The present invention relates to an optical transceiver, in particular, the invention relates to an optical transceiver having inner fibers that optically couple an external optical connector with optical devices implemented within the optical transceiver.
2. Background Arts
One type of optical apparatus is generally called as an optical transceiver that concurrently implements functions of an optical transmission and an optical reception. An optical transceiver installs a semiconductor laser diode for a light source of the optical transmission and a semiconductor photodiode for a transducer of the optical reception. When an optical transceiver implements as the light source a laser diode of the type of vertical cavity surface emitting laser diode (VCSEL), a function to bend an optical axis of the light source by a right angle becomes inevitable. That is, a VCSEL is mounted on a circuit board, while, an external connector set within an optical receptacle of the optical transceiver has an optical axis perpendicular to the circuit board. Accordingly, the light coming from the VCSEL is necessary to be bent by a right angle to optically couple with the external optical connector. One or more inner fibers may optically couple the optical device with the optical connector, refer to a Japanese Patent Application laid open No. 2008-090232.
The inner fibers coupling optical component inevitably have surplus lengths to absorb dimensional tolerances of the optical components and reduce optical losses due to stresses applied thereto. Treatments of the surplus lengths in the inner fibers become substantial in the mechanical design of an optical transceiver. The optical transceiver disclosed in the prior patent document above connect a lens assembly, to which optical fibers are coupled, with a circuit board by a flexible printed circuit (FPC) board to absorb dimensional tolerances of the components. However, FPC boards as additional parts raise assembling costs of the optical transceiver.